pem(3)                              OpenSSL                             pem(3)



NAME
       PEM - PEM routines

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/pem.h>

        EVP_PKEY *PEM_read_bio_PrivateKey(BIO *bp, EVP_PKEY **x,
                                               pem_password_cb *cb, void *u);

        EVP_PKEY *PEM_read_PrivateKey(FILE *fp, EVP_PKEY **x,
                                               pem_password_cb *cb, void *u);

        int PEM_write_bio_PrivateKey(BIO *bp, EVP_PKEY *x, const EVP_CIPHER *enc,
                                               unsigned char *kstr, int klen,
                                               pem_password_cb *cb, void *u);

        int PEM_write_PrivateKey(FILE *fp, EVP_PKEY *x, const EVP_CIPHER *enc,
                                               unsigned char *kstr, int klen,
                                               pem_password_cb *cb, void *u);

        int PEM_write_bio_PKCS8PrivateKey(BIO *bp, EVP_PKEY *x, const EVP_CIPHER *enc,
                                               char *kstr, int klen,
                                               pem_password_cb *cb, void *u);

        int PEM_write_PKCS8PrivateKey(FILE *fp, EVP_PKEY *x, const EVP_CIPHER *enc,
                                               char *kstr, int klen,
                                               pem_password_cb *cb, void *u);

        int PEM_write_bio_PKCS8PrivateKey_nid(BIO *bp, EVP_PKEY *x, int nid,
                                               char *kstr, int klen,
                                               pem_password_cb *cb, void *u);

        int PEM_write_PKCS8PrivateKey_nid(FILE *fp, EVP_PKEY *x, int nid,
                                               char *kstr, int klen,
                                               pem_password_cb *cb, void *u);

        EVP_PKEY *PEM_read_bio_PUBKEY(BIO *bp, EVP_PKEY **x,
                                               pem_password_cb *cb, void *u);

        EVP_PKEY *PEM_read_PUBKEY(FILE *fp, EVP_PKEY **x,
                                               pem_password_cb *cb, void *u);

        int PEM_write_bio_PUBKEY(BIO *bp, EVP_PKEY *x);
        int PEM_write_PUBKEY(FILE *fp, EVP_PKEY *x);

        RSA *PEM_read_bio_RSAPrivateKey(BIO *bp, RSA **x,
                                               pem_password_cb *cb, void *u);

        RSA *PEM_read_RSAPrivateKey(FILE *fp, RSA **x,
                                               pem_password_cb *cb, void *u);

        int PEM_write_bio_RSAPrivateKey(BIO *bp, RSA *x, const EVP_CIPHER *enc,
                                               unsigned char *kstr, int klen,
                                               pem_password_cb *cb, void *u);

        int PEM_write_RSAPrivateKey(FILE *fp, RSA *x, const EVP_CIPHER *enc,
                                               unsigned char *kstr, int klen,
                                               pem_password_cb *cb, void *u);

        RSA *PEM_read_bio_RSAPublicKey(BIO *bp, RSA **x,
                                               pem_password_cb *cb, void *u);

        RSA *PEM_read_RSAPublicKey(FILE *fp, RSA **x,
                                               pem_password_cb *cb, void *u);

        int PEM_write_bio_RSAPublicKey(BIO *bp, RSA *x);

        int PEM_write_RSAPublicKey(FILE *fp, RSA *x);

        RSA *PEM_read_bio_RSA_PUBKEY(BIO *bp, RSA **x,
                                               pem_password_cb *cb, void *u);

        RSA *PEM_read_RSA_PUBKEY(FILE *fp, RSA **x,
                                               pem_password_cb *cb, void *u);

        int PEM_write_bio_RSA_PUBKEY(BIO *bp, RSA *x);

        int PEM_write_RSA_PUBKEY(FILE *fp, RSA *x);

        DSA *PEM_read_bio_DSAPrivateKey(BIO *bp, DSA **x,
                                               pem_password_cb *cb, void *u);

        DSA *PEM_read_DSAPrivateKey(FILE *fp, DSA **x,
                                               pem_password_cb *cb, void *u);

        int PEM_write_bio_DSAPrivateKey(BIO *bp, DSA *x, const EVP_CIPHER *enc,
                                               unsigned char *kstr, int klen,
                                               pem_password_cb *cb, void *u);

        int PEM_write_DSAPrivateKey(FILE *fp, DSA *x, const EVP_CIPHER *enc,
                                               unsigned char *kstr, int klen,
                                               pem_password_cb *cb, void *u);

        DSA *PEM_read_bio_DSA_PUBKEY(BIO *bp, DSA **x,
                                               pem_password_cb *cb, void *u);

        DSA *PEM_read_DSA_PUBKEY(FILE *fp, DSA **x,
                                               pem_password_cb *cb, void *u);

        int PEM_write_bio_DSA_PUBKEY(BIO *bp, DSA *x);

        int PEM_write_DSA_PUBKEY(FILE *fp, DSA *x);

        DSA *PEM_read_bio_DSAparams(BIO *bp, DSA **x, pem_password_cb *cb, void *u);

        DSA *PEM_read_DSAparams(FILE *fp, DSA **x, pem_password_cb *cb, void *u);

        int PEM_write_bio_DSAparams(BIO *bp, DSA *x);

        int PEM_write_DSAparams(FILE *fp, DSA *x);

        DH *PEM_read_bio_DHparams(BIO *bp, DH **x, pem_password_cb *cb, void *u);

        DH *PEM_read_DHparams(FILE *fp, DH **x, pem_password_cb *cb, void *u);

        int PEM_write_bio_DHparams(BIO *bp, DH *x);

        int PEM_write_DHparams(FILE *fp, DH *x);

        X509 *PEM_read_bio_X509(BIO *bp, X509 **x, pem_password_cb *cb, void *u);

        X509 *PEM_read_X509(FILE *fp, X509 **x, pem_password_cb *cb, void *u);

        int PEM_write_bio_X509(BIO *bp, X509 *x);

        int PEM_write_X509(FILE *fp, X509 *x);

        X509 *PEM_read_bio_X509_AUX(BIO *bp, X509 **x, pem_password_cb *cb, void *u);

        X509 *PEM_read_X509_AUX(FILE *fp, X509 **x, pem_password_cb *cb, void *u);

        int PEM_write_bio_X509_AUX(BIO *bp, X509 *x);

        int PEM_write_X509_AUX(FILE *fp, X509 *x);

        X509_REQ *PEM_read_bio_X509_REQ(BIO *bp, X509_REQ **x,
                                               pem_password_cb *cb, void *u);

        X509_REQ *PEM_read_X509_REQ(FILE *fp, X509_REQ **x,
                                               pem_password_cb *cb, void *u);

        int PEM_write_bio_X509_REQ(BIO *bp, X509_REQ *x);

        int PEM_write_X509_REQ(FILE *fp, X509_REQ *x);

        int PEM_write_bio_X509_REQ_NEW(BIO *bp, X509_REQ *x);

        int PEM_write_X509_REQ_NEW(FILE *fp, X509_REQ *x);

        X509_CRL *PEM_read_bio_X509_CRL(BIO *bp, X509_CRL **x,
                                               pem_password_cb *cb, void *u);
        X509_CRL *PEM_read_X509_CRL(FILE *fp, X509_CRL **x,
                                               pem_password_cb *cb, void *u);
        int PEM_write_bio_X509_CRL(BIO *bp, X509_CRL *x);
        int PEM_write_X509_CRL(FILE *fp, X509_CRL *x);

        PKCS7 *PEM_read_bio_PKCS7(BIO *bp, PKCS7 **x, pem_password_cb *cb, void *u);

        PKCS7 *PEM_read_PKCS7(FILE *fp, PKCS7 **x, pem_password_cb *cb, void *u);

        int PEM_write_bio_PKCS7(BIO *bp, PKCS7 *x);

        int PEM_write_PKCS7(FILE *fp, PKCS7 *x);

        NETSCAPE_CERT_SEQUENCE *PEM_read_bio_NETSCAPE_CERT_SEQUENCE(BIO *bp,
                                                       NETSCAPE_CERT_SEQUENCE **x,
                                                       pem_password_cb *cb, void *u);

        NETSCAPE_CERT_SEQUENCE *PEM_read_NETSCAPE_CERT_SEQUENCE(FILE *fp,
                                                       NETSCAPE_CERT_SEQUENCE **x,
                                                       pem_password_cb *cb, void *u);

        int PEM_write_bio_NETSCAPE_CERT_SEQUENCE(BIO *bp, NETSCAPE_CERT_SEQUENCE *x);

        int PEM_write_NETSCAPE_CERT_SEQUENCE(FILE *fp, NETSCAPE_CERT_SEQUENCE *x);

DESCRIPTION
       The PEM functions read or write structures in PEM format. In this sense
       PEM format is simply base64 encoded data surrounded by header lines.

       For more details about the meaning of arguments see the PEM FUNCTION
       ARGUMENTS section.

       Each operation has four functions associated with it. For clarity the
       term "foobar functions" will be used to collectively refer to the
       PEM_read_bio_foobar(), PEM_read_foobar(), PEM_write_bio_foobar() and
       PEM_write_foobar() functions.

       The PrivateKey functions read or write a private key in PEM format
       using an EVP_PKEY structure. The write routines use "traditional" pri-
       vate key format and can handle both RSA and DSA private keys. The read
       functions can additionally transparently handle PKCS#8 format encrypted
       and unencrypted keys too.

       PEM_write_bio_PKCS8PrivateKey() and PEM_write_PKCS8PrivateKey() write a
       private key in an EVP_PKEY structure in PKCS#8 EncryptedPrivateKeyInfo
       format using PKCS#5 v2.0 password based encryption algorithms. The
       cipher argument specifies the encryption algoritm to use: unlike all
       other PEM routines the encryption is applied at the PKCS#8 level and
       not in the PEM headers. If cipher is NULL then no encryption is used
       and a PKCS#8 PrivateKeyInfo structure is used instead.

       PEM_write_bio_PKCS8PrivateKey_nid() and PEM_write_PKCS8PrivateKey_nid()
       also write out a private key as a PKCS#8 EncryptedPrivateKeyInfo how-
       ever it uses PKCS#5 v1.5 or PKCS#12 encryption algorithms instead. The
       algorithm to use is specified in the nid parameter and should be the
       NID of the corresponding OBJECT IDENTIFIER (see NOTES section).

       The PUBKEY functions process a public key using an EVP_PKEY structure.
       The public key is encoded as a SubjectPublicKeyInfo structure.

       The RSAPrivateKey functions process an RSA private key using an RSA
       structure. It handles the same formats as the PrivateKey functions but
       an error occurs if the private key is not RSA.

       The RSAPublicKey functions process an RSA public key using an RSA
       structure. The public key is encoded using a PKCS#1 RSAPublicKey struc-
       ture.

       The RSA_PUBKEY functions also process an RSA public key using an RSA
       structure. However the public key is encoded using a SubjectPublicKey-
       Info structure and an error occurs if the public key is not RSA.

       The DSAPrivateKey functions process a DSA private key using a DSA
       structure. It handles the same formats as the PrivateKey functions but
       an error occurs if the private key is not DSA.

       The DSA_PUBKEY functions process a DSA public key using a DSA struc-
       ture. The public key is encoded using a SubjectPublicKeyInfo structure
       and an error occurs if the public key is not DSA.

       The DSAparams functions process DSA parameters using a DSA structure.
       The parameters are encoded using a foobar structure.

       The DHparams functions process DH parameters using a DH structure. The
       parameters are encoded using a PKCS#3 DHparameter structure.

       The X509 functions process an X509 certificate using an X509 structure.
       They will also process a trusted X509 certificate but any trust set-
       tings are discarded.

       The X509_AUX functions process a trusted X509 certificate using an X509
       structure.

       The X509_REQ and X509_REQ_NEW functions process a PKCS#10 certificate
       request using an X509_REQ structure. The X509_REQ write functions use
       CERTIFICATE REQUEST in the header whereas the X509_REQ_NEW functions
       use NEW CERTIFICATE REQUEST (as required by some CAs). The X509_REQ
       read functions will handle either form so there are no X509_REQ_NEW
       read functions.

       The X509_CRL functions process an X509 CRL using an X509_CRL structure.

       The PKCS7 functions process a PKCS#7 ContentInfo using a PKCS7 struc-
       ture.

       The NETSCAPE_CERT_SEQUENCE functions process a Netscape Certificate
       Sequence using a NETSCAPE_CERT_SEQUENCE structure.

PEM FUNCTION ARGUMENTS
       The PEM functions have many common arguments.

       The bp BIO parameter (if present) specifies the BIO to read from or
       write to.

       The fp FILE parameter (if present) specifies the FILE pointer to read
       from or write to.

       The PEM read functions all take an argument TYPE **x and return a TYPE
       * pointer. Where TYPE is whatever structure the function uses. If x is
       NULL then the parameter is ignored. If x is not NULL but *x is NULL
       then the structure returned will be written to *x. If neither x nor *x
       is NULL then an attempt is made to reuse the structure at *x (but see
       BUGS and EXAMPLES sections).  Irrespective of the value of x a pointer
       to the structure is always returned (or NULL if an error occurred).

       The PEM functions which write private keys take an enc parameter which
       specifies the encryption algorithm to use, encryption is done at the
       PEM level. If this parameter is set to NULL then the private key is
       written in unencrypted form.

       The cb argument is the callback to use when querying for the pass
       phrase used for encrypted PEM structures (normally only private keys).

       For the PEM write routines if the kstr parameter is not NULL then klen
       bytes at kstr are used as the passphrase and cb is ignored.

       If the cb parameters is set to NULL and the u parameter is not NULL
       then the u parameter is interpreted as a null terminated string to use
       as the passphrase. If both cb and u are NULL then the default callback
       routine is used which will typically prompt for the passphrase on the
       current terminal with echoing turned off.

       The default passphrase callback is sometimes inappropriate (for example
       in a GUI application) so an alternative can be supplied. The callback
       routine has the following form:

        int cb(char *buf, int size, int rwflag, void *u);

       buf is the buffer to write the passphrase to. size is the maximum
       length of the passphrase (i.e. the size of buf). rwflag is a flag which
       is set to 0 when reading and 1 when writing. A typical routine will ask
       the user to verify the passphrase (for example by prompting for it
       twice) if rwflag is 1. The u parameter has the same value as the u
       parameter passed to the PEM routine. It allows arbitrary data to be
       passed to the callback by the application (for example a window handle
       in a GUI application). The callback must return the number of charac-
       ters in the passphrase or 0 if an error occurred.

EXAMPLES
       Although the PEM routines take several arguments in almost all applica-
       tions most of them are set to 0 or NULL.

       Read a certificate in PEM format from a BIO:

        X509 *x;
        x = PEM_read_bio_X509(bp, NULL, 0, NULL);
        if (x == NULL)
               {
               /* Error */
               }

       Alternative method:

        X509 *x = NULL;
        if (!PEM_read_bio_X509(bp, &x, 0, NULL))
               {
               /* Error */
               }

       Write a certificate to a BIO:

        if (!PEM_write_bio_X509(bp, x))
               {
               /* Error */
               }

       Write an unencrypted private key to a FILE pointer:

        if (!PEM_write_PrivateKey(fp, key, NULL, NULL, 0, 0, NULL))
               {
               /* Error */
               }

       Write a private key (using traditional format) to a BIO using triple
       DES encryption, the pass phrase is prompted for:

        if (!PEM_write_bio_PrivateKey(bp, key, EVP_des_ede3_cbc(), NULL, 0, 0, NULL))
               {
               /* Error */
               }

       Write a private key (using PKCS#8 format) to a BIO using triple DES
       encryption, using the pass phrase "hello":

        if (!PEM_write_bio_PKCS8PrivateKey(bp, key, EVP_des_ede3_cbc(), NULL, 0, 0, "hello"))
               {
               /* Error */
               }

       Read a private key from a BIO using the pass phrase "hello":

        key = PEM_read_bio_PrivateKey(bp, NULL, 0, "hello");
        if (key == NULL)
               {
               /* Error */
               }

       Read a private key from a BIO using a pass phrase callback:

        key = PEM_read_bio_PrivateKey(bp, NULL, pass_cb, "My Private Key");
        if (key == NULL)
               {
               /* Error */
               }

       Skeleton pass phrase callback:

        int pass_cb(char *buf, int size, int rwflag, void *u);
               {
               int len;
               char *tmp;
               /* We'd probably do something else if 'rwflag' is 1 */
               printf("Enter pass phrase for \"%s\"\n", u);

               /* get pass phrase, length 'len' into 'tmp' */
               tmp = "hello";
               len = strlen(tmp);

               if (len <= 0) return 0;
               /* if too long, truncate */
               if (len > size) len = size;
               memcpy(buf, tmp, len);
               return len;
               }

NOTES
       The old PrivateKey write routines are retained for compatibility.  New
       applications should write private keys using the
       PEM_write_bio_PKCS8PrivateKey() or PEM_write_PKCS8PrivateKey() routines
       because they are more secure (they use an iteration count of 2048
       whereas the traditional routines use a count of 1) unless compatibility
       with older versions of OpenSSL is important.

       The PrivateKey read routines can be used in all applications because
       they handle all formats transparently.

       A frequent cause of problems is attempting to use the PEM routines like
       this:

        X509 *x;
        PEM_read_bio_X509(bp, &x, 0, NULL);

       this is a bug because an attempt will be made to reuse the data at x
       which is an uninitialised pointer.

PEM ENCRYPTION FORMAT
       This old PrivateKey routines use a non standard technique for encryp-
       tion.

       The private key (or other data) takes the following form:

        -----BEGIN RSA PRIVATE KEY-----
        Proc-Type: 4,ENCRYPTED
        DEK-Info: DES-EDE3-CBC,3F17F5316E2BAC89

        ...base64 encoded data...
        -----END RSA PRIVATE KEY-----

       The line beginning DEK-Info contains two comma separated pieces of
       information: the encryption algorithm name as used by EVP_get_cipherby-
       name() and an 8 byte salt encoded as a set of hexadecimal digits.

       After this is the base64 encoded encrypted data.

       The encryption key is determined using EVP_bytestokey(), using salt and
       an iteration count of 1. The IV used is the value of salt and *not* the
       IV returned by EVP_bytestokey().

BUGS
       The PEM read routines in some versions of OpenSSL will not correctly
       reuse an existing structure. Therefore the following:

        PEM_read_bio_X509(bp, &x, 0, NULL);

       where x already contains a valid certificate, may not work, whereas:

        X509_free(x);
        x = PEM_read_bio_X509(bp, NULL, 0, NULL);

       is guaranteed to work.

RETURN CODES
       The read routines return either a pointer to the structure read or NULL
       if an error occurred.

       The write routines return 1 for success or 0 for failure.



0.9.9-dev                         2005-03-25                            pem(3)

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